It’s hard out there for a penguin. As viewers of the French film Winged Migration might remember, a long life is by no means certain for the emblematic flightless birds of the Southern Hemisphere.

As of September 2010, 10 of the world’s 17 (or, many biologists now maintain, 18) penguin species had experienced precipitous declines in population in the last few years, and to multiple causes—predation being the least of them, though predation by introduced mammals such as feral cats and dogs is still a very real cause of death.

Thirteen of those species are now listed internationally as endangered or threatened.

Some of them will likely go extinct sometime in the 21st century, just as so many species of penguins have disappeared in the past—for the world has seen more than a hundred of them over the last 50 million years or so, including an ancestral variety that stood more than 6 feet (1.8 meters) tall.

Penguins are broadly distributed throughout the Southern Hemisphere. One species lives in the Galapagos Islands, near the equator, but most others live well to the south, in Antarctica, the sub-Antarctic islands, and southern Oceania, South America, and Africa. These regions, part of what economic geographers call the Global South, have been largely undeveloped industrially. Until recently, that is, for now human enterprises, particularly mineral extraction and factory fishing, increasingly impinge there on wildlife populations of all kinds.

Chronic oil pollution has taken its toll on penguins, a matter documented in Dyan deNapoli’s recent book The Great Penguin Rescue (Free Press, 2010). So have diseases of various kinds. Many penguins, though, have been falling victim instead to a lack of food resources—starvation, in other words, brought about by overfishing in the planet’s contested southern waters, and by rapidly changing climatic conditions. As Carl Safina writes in his recent book The View from Lazy Point (Henry Holt, 2011), the air of the Antarctic “is warming several times faster than the global average.”

In the last 40-odd years, that increase has been on the order of ten degrees Fahrenheit, which has dramatically remade the icy habitat of several species. It has also dramatically reduced the population of krill, the small crustaceans on which so many animals, from whales to penguins, depend. The krill are declining, in turn, because the loss of sea ice in their habitat has altered the growth cycle of the marine algae on which they feed—a complex illustration of the fact that a change in one part of the food chain has effects all along the line.

As Safina recounts, for the Adélie and chinstrap varieties of the Antarctic, this has meant a decline in numbers of almost 50 percent. Moreover, whereas a few decades ago about 40 percent of young penguins survived to reproduce, today the number is only about 10 percent. Emperor penguins, adapted over millions of years to the Antarctic winter through a technique called “huddling” and through lowering their metabolic rate in times of extreme cold, have been suffering as well; it is projected that the species will face extinction within fifty years, faster than they can adapt to the changing, warming conditions. Or, as the authors of a recent paper in the Proceedings of the National Academy of Science put it, “To avoid extinction, Emperor penguins will have to adapt, migrate or change the timing of their growth stages. However, given the future projected increases in [greenhouse gas] and its effect on Antarctic climate, evolution or migration seem unlikely for such long-lived species at the remote southern end of the Earth.”

Even in a best-case scenario, the species is very likely to suffer a catastrophic population collapse by the year 2100, resulting in “quasi-extinction,” or the survival of only some 5 percent of the emperors. Meanwhile, Northern rockhopper penguins, which live in the South Atlantic, are down 90 percent in number from a census undertaken in the late 1950s. In 1960, there were some 150,000 breeding pairs of African penguins. In 2000, there were about 50,000. The number is about 25,000 today.

Climate change is documentable, and even if the fact of it is contested politically, the numbers are there for all to see. Hunger is documentable, too. The BBC recently reported that 500 dead penguins washed ashore on a Brazilian beach last summer—in the height, that is to say, of the austral winter. Biologists conducted an autopsy whose results were inconclusive as to root cause: Overfishing of the nearby waters, some said, was to blame, though others posited that winter storms may have been the deciding factor. Whatever the case, the penguins died of starvation: their stomachs were absolutely and undeniably empty.

Efforts are being made internationally to protect penguin species. In late 2008, for example, the government of Argentina, working with the Wildlife Conservation Society and the Bronx Zoo, set aside a 250-square-mile area along the Patagonia coast and offshore islands for a marine park, the home of at least half a million Magellanic penguins, as well as the only remaining population of South American fur seals in the region.

But more, much more, needs to be done. Do we want it said that a human child born today may live to witness the disappearance of penguins from the planet on which they have lived for the last 50 million years? We have only a short time in which to act if the answer is to be no.